A physical unclonable function (PUF) is a technology related to the field of authentication and security and generates a physically unique code. Conventionally, there have been suggested technologies, which generate unique keys by using a SRAM, a ring oscillator, a latch, etc., depend on their physical characteristics.
In this regard, Korean Patent No. 1408619 (Title of Invention: Physical Unclonable Function System Based on Capacitance Variations) describes a physical unclonable function system, which includes two or more physical unclonable function (PUF) cells and a control signal generation unit that generates a control signal for controlling operation of each of the physical unclonable function cells, wherein each of the physical unclonable function cells operates according to the control signal, and includes a charge sharing circuit that includes a circuit where two or more capacitors are arranged in parallel, a comparator that detects a capacitance difference of some of the capacitors in the charge sharing circuit, and a logical exclusive-OR gate that implements a logical exclusive OR for an input signal (challenge) and a signal output from the comparator to output an output signal (response) as a result of the logical exclusive OR.
Meanwhile, since there has been no technology relating to a method for generating a key by using a memory being used in most devices, a method that can embody the PUF without requiring a separate significant correction within a memory is necessary.